Emergency Medical Services (EMS) personnel who work 12- to 24-hour shifts may be at significant risk for fatigue that could lead to occupational injury, according to new research led by the University of Pittsburgh School of Medicine.

The findings, published online in the journal Occupational & Environmental Medicine, found that shift length is associated with occupational injury.

"The nature of the EMS clinician's job requires physical strength to lift and move patients, cognitive capacity and temperament to deliver medical care in uniquely stressful and uncontrolled situations, and often requires operating a motor vehicle," said lead author Matthew Weaver, Ph.D., who conducted the research while employed in Pitt's Department of Emergency Medicine. "There are many factors that may impact safety. Our study identifies a preventable exposure - extended shift length - associated with injury, warranting trials to test potential interventions, such as periodic assessments of worker fatigue during shifts or adjusting work hours to accommodate on-shift rest periods."

Dr. Weaver and his colleagues examined three years of occupational safety and illness records of nearly a million work shifts for 4,382 EMS employees across the country. The risk of an occupational injury or illness increased as shifts got longer. Compared with shifts of less than 12 hours duration, shifts greater than or equal to 12 hours increased risk of an injury by 50 percent after controlling for other relevant factors, such as employer, night vs. day shift, employment status and how often the EMS crew had previously worked together. Shifts longer than 16 and less than or equal to 24 hours more than doubled the risk of on-the-job injury compared to eight-hour shifts.

Since they performed an observational study that analyzed existing records, the researchers caution that no definitive conclusions can be drawn about cause and effect. Injuries to patients were not collected as part of this study.

"There is little evidence in this area to guide scheduling practices," said Dr. Weaver. "Future research should involve a wide variety of EMS agencies in different settings to determine how to structure staffing to deliver care in a safe and effective manner."